High temperature resistant polymeric cyclosilazanes



United States Patent 3,431,222 HIGH TEMPERATURE RESISTANT POLYMERICCYCLOSILAZANES Walter Fink, Zurich, Switzerland, assignor to MonsantoCompany, St. Louis, Mo., a corporation of Delaware No Drawing.Continuation-impart of applicationSer. No. 496,702, Oct. 15, 1965, whichis a continuation-in-part of application Ser. No. 399,814, Sept. 28,1964. This application June 22, 1967, Ser. No. 647,944

U.S. Cl. 260-2 Int. Cl. C08g 31/30 24 Claims in the presence of acatalyst, e.g., an alkali metal or metal hydride, to split off hydrogen,the (A) compounds being formed when R separates the nitrogen atoms bymore than 3 aliphatic carbon atoms or meta or para spaced nitrogen atomson an aromatic ring, otherwise the (A') compounds are formed.

This application is a continuation'in-part of copending application Ser.No. 496,702, filed Oct. 15, 1965, now abandoned which is acontinuation-in-part of application Ser. No. 399,814, filed Sept. 28,1964, now abandoned.

The present invention relates to a novel class of high temperatureresistant polymers and a process of preparing same.

The novel polymers consist of repeating structural units of the generalformula I: R 9 wherein preferably R and R are identical or different andrepresent fluorine atoms, hydrogen atoms or hydrocarbyls, i.e. groupscontaining hydrogen and carbon which can be saturated or unsaturatedaliphatic or aromatlc, and which can have halogen atoms, alkoxy groups,aroxy groups and silyl groups, ie SiR groups where R is hydrocarbyl orhydrocarbyl substituted with halogens, alkoxy or aroxy groups assubstituents, or which form a heterocyclic group made by a chain ofmethylene groups joined through the silicon atom to which R and R areattached, R is a hydrocarbylene group or hydrocarbylene ether groupwhich, like the hydrocarbyl groups, can have halogen atoms, alkoxygroups, aroxy groups and silyl groups as substituents, a is zero or 1and p represents the number of repeating units. All R, R R etc. groupscan also contain other substituents than enumerated above as indicatedby specifically named substituents below.

These compounds are obtained by decomposition of certain silazanes whichcan be generally expressed by the ZY YZ "ice The starting compounds (B)suitable for carrying out the invention contain an amine radical Zcleavable in the reaction and which, together with a hydrogen atom Y, isreleased during the cyclization and polymerization process. R to R and aare defined as before. The preferred amine radicals Z are derived fromprimary amines which are easily volatile at the reaction temperature.Examples are methylamine, ethylamine, n-propylamine, ispropylamine,n-butylamine, iso-butylamine, sec-butylamine, tert-butylamine,methoxymethylamine and rnethoxyethylamine. However, the amine radicalscan also be derived from cycloaliphatic, araliphatic and aromaticamines, so far as these are volatile at the reaction temperature. Thechoice of the appropriate amine may also be directed by the boilingpoint of the derived diaminosilane and by the destiny of the amine whenit is split off again. The amine radicals derived from secondary aminesare less preferred. It was found that the compounds having tertiaryamine groups in most of the cases yield only half the amount of thedesired polymeric cyclodisilazanes since a detrimental rearrangementoccurs.

Thus, the preferred starting compounds are more specifically representedby the formula (C) R HNSi(R R NH-R ,,-NH-Si(R R )-NHR wherein R to R anda are defined as above and NHR identifies a radical of a primary amineas mentioned above and which is released in the reaction.

The formation of the polymeric cyclodisilazanes probably proceeds in allcases via an unstable, intermediate bis(silylimide) which quicklypolymerizes under formation of very stable four-membered rings. Thisreaction can be schematized as follows:

The starting compounds as generalized by the Formula B and more closelyspecified by the Formula C and which here further are denotedN,N-bis(aminosilyl) amines, have not been known up to now. They areeasily obtained by transamination of diaminosilanes which are well knowncompounds obeying to the formula wherein R to R are defined as before,with a diamine of the formula wherein R and a are defined as before.

Numerous diaminosilanes showing the Formula D, or dichlorosilanes fromwhich the former can be prepared, are known in the prior art. Examplesof R and R which are also found in the polymers of invention as becomesevident on considering the equation (a) are: hydrogen, fluorine,alkenyls, alkyls and alkynyls such as methyl, ethyl, vinyl, ethynyl,n-propyl, isopropyl, allyl, propenyl, propargyl, propynyl, n-butyl,iso-butyl, sec-butyl, tertbutyl, methallyl, l-butenyl, crotyl,butadienyl, l-butynyl, Z-butynyl, 1-buten-2-ynyl and higher aliphaticradicals having up to 24 carbon atoms such as undecenyl, dodecyl,myristyl, oleyl, tetracosyl; cycloalkyls, cycloalkenyls andcycloalkynyls such as cyclopentyl, cyclopenteyl, cyclopentadienyl,cyclohexyl, cyclohexenyl, cyclohexynyl, cyclohexadienyl and largeralicyclic radicals having up to 12 carbon atoms such as cyclododecyl,cyclooctyl, cyclooctatrienyl, cyclododecatrienyl, hicyclohexyl;aralkyls, aralkenyls and aralkynyls, such as benzyl, cuminyl,phenylethyl, styryl, phenylethynyl, phenylpropyl, 3-phenylallyl,2-phenylallyl, cinnamyl, l-phenylpropynyl, diphenylmethyl,triphenylmethyl, a-naphthylmethyl, fl-naphthylmethyl, a naphthylethyl,naphthylethyl, oz naphthylethenyl, fl-naphthylethenyl,a-naphthylethynyl, fi-naphthylethynyl; alkaryls, alkenylaryls andalkynylaryls such as tolyl, xylyl, mesityl, duryl, ethylphenyl, cumyl,methyl, vinylphenyl, ethynylphenyl, propargylphenyl, propynylphenyl,tert-butylphenyl, l-vinylnaphthyl, 2-viny1naphthyl, l-ethynylnaphthyl,2-ethynylnaphthyl; aryls such as phenyl, o-biphenylyl, m-biphenylyl,p-biphenylyl, p-terphenylyl, m-terphenylyl, l-naphthyl, Z-naphthyl,2-anthryl, 9-anthryl, l-phenanthryl, Z-phenanthryl, 3-phenanthryl,4-phenanthryl, 9-phenanthryl; and heterocyclic radicals such as pyrryl,furyl, benzofuryl, thienyl, pyrrolinyl, pyrazolyl, pyrazolinyl,imidazolyl, thiazolyl, oxa- Zolyl, isooxazolyl, pyrazinyl, pyrimidyl,pyridazinyl, pyridyl, pyranyl, thiopyranyl, piperidyl, morpholinyl,thiazinyl, triazinyl, quinolyl, quinazolyl, quinoxalyl, indolyl,carbazolyl. If an NH group is present it is preferably substituted likein N-methylpyrryl, N-trimethylsilylimidazolyl, etc.

It was found that the enumerated hydrocarbon radicals as well as theheterocyclic radicals can possess substituents and these substituentswill not hinder the success of the reaction. Examples of possiblesubstituents are Cl, Br, I, F, -OR SR COR CSR COOR have the samesignificance as before; furthermore, Si, B and P-containing radicals asspecified above for R and R Examples of some simple representatives ofthe large class of halogenated hydrocarbyls are chloromethyl,dichloromethyl, trichloromethyl, bromomethyl, dibrornomethyl,tribromomethyl, fiuoromethyl, difiuoromethyl, trifluoromethyl, lchloroethyl, 2-chloroethyl, l-bromoethyl, 2-bromoethyl, l-fiuoroethyl,2-fluoroethyl, 1,2-dichloroethyl, 1,2-difluoroethyl, 2-trichloroethyl,2-trifiuoroethyl, pentafluoroethyl, 2-chlorovinyl, l-chlorovinyl,1,2-dichlorovinyl, trichlorovinyl, trifiuorovinyl, chloroethynyl,fiuoroethynyl, chlorophenyl, dichlorophenyl, trichlorophenyl,bromophenyl, fluorophenyl, difluorophenyl, trifluorophenyl,pentafluorophenyl.

Examples of some hydrocarbyloxy substituents showing the formula R O aremethoxy, ethoxy, dimethylaminoethoxy, vinyloxy, n-propoxy, iso-propoxy,bis(trimethylsilyl)-amino-iso-propoxy, 1 propeneoxy, 2 propeneoxy,iso-propeneoxy, n-butoxy, iso-butoxy, sec-butoxy,

tert-butoxy, crotoXy, n-amoxy, iso-amoxy, n-octanoxy, IO-undecyleneoxy,lauroxy, stearoxy, phenylmethoxy, styryloxy, phenylethynyloxy,p-allylphenoxy, phenoxy, toloxy, xyloxy, 3-biphenylyloxy, l-naphthoxy,2-naphthoxy, m-diphenylaminophenoxy, asaryloxy, including the thioanalogues having sulfur in the place of oxygen and showing the formula RS-. Especially useful substituents possess several ether groupingsbranched or in sequence such as methoxymethyleneoxy, methoxyethyleneoxy,ethoxyethyleneoxy, tert-butoxy-tert-butyleneoxy, veratroxy, anisoxy,phenetoxy, 3,4-dimethoxyphenenyloxy, 3- phenoxyphenyleneoxy, 3-phenoxy 4methoxyphenenyloxy, 3,4-diphenoxyphenenyloxy, polymethyleneoxy of theformula R OCH (OCH O-, wherein b is defined as before and R is anetherifying or esterifying terminal radical as usual in polyoxymethylenecompounds, the parent substituents having ethylene or propylene in theplace of methylene. R normally has not more than 24 carbon atoms. Thecited hydrocarbyloxy radicals can also be directly attached to thesilicon atoms as provided under 4 the definition of R and R Otherpoly(alkylene ether) radicals possess the formula or ROCH2CH2CH2(OCH2CH2CH2) wherein R9 and b again are defined as before.They are obtained by action of ethylene oxide or propylene oxide onhydroxyethyl or hydroxypropyl attached to silicon.

A free hydroxyl or mercapto group can be present as a substituent in thepolymers. The simplest representatives of the class are hydroxyethyl andmercaptoethyl. Cross-linking may occur during the polymerization. Thereaction may be carried out using the sodium, potassium or lithium salt.The HO and HS groups can be restored by ion exchange.

Examples of some acyl substituents showing the formula R C H O areacetyl, n-propionyl, acrylyl, crotonyl, propiolyl, nbutyryl,iso-butyryl, amoyl, pivalyl, enanthyl, caprylyl, lauroyl, myristoyl,oleolyl, stearoyl, phenylacetyl, diphenylacetyl, cinnamoyl, benzoyl,naphthoyl, cumoyl, 4-biphenylylcarbonyl, anisoyl, phenetoyl, veratroyl,2,3,4,- 2,4,5- and 3,4,5-trimethoxybenzoyl, p-diphenylaminobenzoyl,trimethylsilylanthranoyl, methoxyacetyl, di methylaminoacetyl,cyanoacetyl, trimethylsilylaminoacetyl, bis-(trimethylsilyl)aminoacetyl, trimethylsiloxyacetyl, trichloroacetyl,trifluoroacetyl, 2-furoyl, 3-furoy1, pyrroyl, including the thioanalogues showing the formula These radicals forming a ketone orthioketone group may be converted by the primary amine released in thereaction into the corresponding radical of a Schiffs base.

Examples of sulfinyl and sulfonyl substituents are those having a S0 orS0 group in the place of the CO group shown in the formula above andthus corresponding to the formulas and ' times in a same substituent.

Examples of some carboxy substituents showing the formula are the freecarboxy group and the ester derivatives such as carbomethoxy,carbethoxy, carbovinyloxy, carbo-npropoxy, carbo 2 propeneoxy,carbo-iso-propeneoxy, carboctoxy, carbundecyleneoxy, carboctadecoxy,carbophenoxy, including the thio analogues showing the formulas Theintermediates containing a free carboxy or other acid group are broughtto reaction in the form of a sodium, potassium or primary amine saltusing in the latter case the same amine which is attached to the siliconand which will be split off during the reaction. The free carboxylicgroups are restored in the polymer by ion exchange which is achieved bytreatment with dilute acid.

Examples of parent sulfo substituents are those having a S0 group in theplace of the CO group shown in the formula above and thus correspondingto the formula The cited ester radicals can be also attached through anitrogen atom and so represent a urethan radical showing the formulaincluding the analogous radicals of thiourethans. During thepolymerization the urethan group may be converted into a urea group.

Examples of the parent sulfamido substituents are those having a S groupin the place of the 00 group shown in the formula above. Contrarily tothe carboxylic derivatives, the free acid exists and hence the radicalscan be expressed by the formula Examples of a further class of estersubstituents showing the formula R4(IfO are acetoxy, acryloyloxy,n-propionyloxy, crotonyloxy, propiolyloxy, tetrolyloxy, n-butyryloxy,iso-butyryloxy, valeryloxy, caproyloxy, caprylyloxy, pelargonyloxy,capryloxy, lauroyloxy, palmitoyloxy, cumoyloxy, phenylacetoxy,phenylacryloyloxy, benzoxy, including the th1o analogues showing theformulas R fis Rfiand R ffs- The radicals of monoesters of dicarboxylicacids, for example, the ethylester of oxalic acid, malonic acid,succinic acid, maleic acid, fumaric acid, adipic acid, phthalic acid,etc. can also be present as substituents. In the course ofpolymerization the acid portion can be cleaved and form an amide withthe primary amine also cleaved in the reaction. The generated alcoholportion still attached to the silicon may incite cross-linking of thepolymer. If the components are appropriately selected, the amide whichis formed can act as a plasticizer or it can be distilled off. Examplesof a further class of ester substituents are those having a S0 group inthe place of the CO group shown in the formula above and thuscorresponding to the formula Examples of some carbamyl substituentsshowing the formula R5R6Nfiare the unsubstituted carbamyl group, thealkali salts thereof, methylcarbamyl, ethylcarbamyl, allylcarbamyl,n-propylcarbamyl, iso-propylcarbamyl, iso-propenylcarbamyl, nbutylcarbamyl, sec-butyl carbamyl, 3-n-butenylcarbamyl,myristylcarbamyl, cyclohexylcar-bamyl, phenylcarbamyl,trimethylsilylcarbamyl, dimethyl-phenylsilylcar- 'bamyl,triphenylsilylcarbamyl, including the similarly disubstituted carbamyls.In general, a carbamyl derived from an identical amine as is directlyattached to the silicon and will be released in the reaction, or from anamine unable to undergo transa-mination (i.e. sterically hindered amineor hardly volatile or non-volatile amine) is preferred.

Examples of parent sulfamyl substituents are those having a S0 group inthe place of the CO group shown in the formula above and thuscorresponding to the formula Examples of some amino substituents showingthe formula R R N- are methylamino, ethylamino, n-propylamino,isopropyla-mino, allylamino, n-butylamino, isobutylamino,stic-butylamino, tert-butylamino, 3-butenylamino, Z-butenylamino,n-amylamino, iso-octylamino, anilino, dodecylamino, cyclohexylamino,cyclohexenylamino, benzylamino, toluidino, p-phenylanilino, cumidino,anisidino, m-methoxyanilino, p-anisylanilino, m-trifiuoromethylanilino,N-diphenylbenzidino, pyrrolino, pyrrolidino, pyrazolino, piperidino,morpholino, thiazino, N-trimethylsilylpiperazino, tetrahydroquinolino,decahydroquinolino. If the primary amino group H N or a secondary aminogroup R HN is present, transamination may occur and cross-linking in thepolymer will result. The transamination can be avoided with tertiaryamine groups R N- such as dimethylamino, diethylamino, dipropyla-rnino,dibutylamino and so on, and heterocyclic amino groups specified above.

The amino groups can also be attached directly to the silicon asprovided under the definition of R and R In such cases the startingmaterial would be: a triaminosilane or a tetraaminosilane. Ifcross-linking in the polymer is not desired, these amino groups (i.e.the "third and, if any, the fourth amino group) preferably are tertiaryones.

Examples of some amido substituents showing the formula are acetamido,chloroacetamido, trifluoroacetamido, benzamido, cyanobenzamido,propionylamide, n-butyrylamido, valerylamido, palmitoylamido,tetracosanoylamido, naphthoylamido, including the parent imido groups,such as phthalimido, pyromellitimido. During the polymerization the acidportion can be split off and form together with the primary amine whichis also released in the reaction, an amide. Simultaneously, a primaryamino group attached through a hydrocarbon radical to the silicon isrestored and will incite cross-linking of the polymer. The amide formedcan be distilled off or remain in the polymer and act as a plasticizer,if the components have been appropriately selected. Thus, a possiblyformed acetamide would distill off, whereas amides derived from highermolecular fatty acids could act as plasticizers.

Examples of sulfoamido substituents are those having a S0 group in theplace of the CO group shown in the formula above and thus correspondingto the formula Examples of some azo, substituents showing the formula RN=N, are methylazo, ethylazo, n-bu'tylazo, iso-butylazo, tert-butylazo,phenylazo, N-phenyl-phenylene-bis-azo.

Examples of some azino substituents showing the formula R R C=NN= areacetaldehyde azino, acetone azino, hexafiuoroacetone azino, benzaldehydeazino, acetophenone azino, 2,4-dichloroacetophenone azino, benzophenoneazino, 4,4bis(n-trimethylsilyl-methylamino)- benzophenone azino.

Examples of some allrylideneamino substituents showing the formula R RC=N- are methyleneamino, ethylideneamino, Z-trifluoroethylideneamino,vinylideneamino, n-propylideneamino, l-ethylbutylideneamino,3-butenylideneamino, benzylideneamino, alpha-methylbenzylideneamino,alpha-phenylbenzylideneamino, cinnamylideneamino.

Examples of some imino substituents showing the for mula R N== are thefree imino group, the alkali salts thereof, methylimino, iso-butylimino,sec-butylimino, allylimino, cycloheptylimino, phenylethylimino,anisylimino, p-dimethylaminophenylenimino, pentafluorophenylimino. Theunsubstituted or substituted imino group attached to hydrocarbonradicals as provided under the definition of R and R form quitegenerally a radical of a Schiffs base. Such substituents can be alsoformed during the polymerization by conversion of aldehyde radicals orketone radicals by the primary amine which is evolved in the reaction.

Examples of some simplest representatives of the large class of cyanatedand nitrated hydrocarbyls are 2-cyanoethyl, 2-nitroethyl,2-cyano-n-propyl, 3-cyano-n-propyl, 2,4-dicyano-n-butyl. Instead ofethyl, n-propyl or n-butyl, other hydrocarbyls, such as has beenmentioned for R and R can be present.

Examples of some silyl substituents showing the formula R Si which aremore closely specified by the formula R Siare trimethylsilyl,tris(trifiuoromethyl) silyl and other trihydrocarbylsilyls containingidentical or different, saturated or unsaturated alkyls, cycloalkyls,aralkyls, alkaryls or aryls such as formerly specified for R and Rincluding silyls in which Si is a constituent of a heterocyclic ringlike in silacyclopentane, silacyclopentene, silacyclohexane,silacyclohexene, silacyclohexadiene, etc.; or which are more closelyspecified by the formulas F Si, F R Si and F(R Siare trifiuorosilyl,methyldifiuorosilyl, dimethyl-fiuorosilyl, phenyl-difluorosilyl,diphenyl-fluorosilyl and other hydrocarbyl-difluorosilyls ordihydrocarbyl-fluorosilyls having hydrocarbyl radicals such as mentionedabove; or which are more closely specified by the formulas (R O) Si-, F(R O)Si, F(R O) Si are trimethoxysilyl, difluoromethoxysilyl,fiuoro-dimethoxysilyl, triphenoxysilyl, difluorophenoxysilyl,fluoro-diphenoxysilyl and other trihydrocarbyloxysilyls,difiuorohydrocarbyloxysilyls and fluoro-dihydrocarbyloxysilylscontaining identical or different, saturated or unsaturated alkoxyls,cycloalkoxyls, aralkoxyls, alkaroxyls or aroxyls such as formerlyspecified for R O or which are more closely specified by the formulas R(R O) Siand R (R O)Si are methyl-dimethoxysilyl, dimethyl-methoxysilyland analogues having a combination of other organic radicals, such asenumerated before.

The silyl substituents can be attached through oxygen and so show theformula R SiO. Some simple representatives are trifluorosiloxy,trimethylsiloxy, trimethoxysiloxy, triphenylsiloxy, triphenoxysiloxy,dimethylmethoxysiloxy, methyl dimethoxysiloxy, diphenyl phenoxysiloxy,phenyl-diphenoxysiloxy, dimethyl-phenoxysiloxy, phenyl-dimethoxysiloxyand analogues having a combination of other organic radicals such asenumerated before.

The silyl substituents can also be attached through nitrogen and so showthe formulas R SiHN-,

R Si(R )N Some simple representatives are trifiuorosilyl methylamino,bistrimethylsilylamino, trimethyland trifiuorosilylamino,(trifiuorosilyl) amino,

silyl-methylamino, bis-(trimethylsilyl)amino, trimethoxysuch asspecified for R and R and for R 0, and such as provided under thedefinition of R Examples of boryl substituents are those having boron inthe place of the silicon shown in the formulas above and being valencysatisfyingly substituted. They can be expressed by the formulas R B-, RBO, R BHN-, R B(R )N- and (R B) N.

Examples of phosphorus-containing substituents are those havingphosphorus in the place of the silicon shown in the formulas above andbeing valency satisfyingly substituted. They can be expressed by theformulas R P, R PO-, R PHN, R P('R )N, (R 1 N including the oxidized andsulfidized, quadruply connected analogues.

In general, all the cited substituents are attached to lower alkyls,alkenyls or alkynyls having 1 to carbon atoms or to phenyl. However,they may also be present on higher aliphatic radicals, or cycloaliphaticradicals, araliphatic radicals and polynuclear aromatic radicals. It maybe noted that in the alicyclic and aromatic radicals the enumeratedsubstituents can be in the ortho, meta or para position with respect tothe position these rings are attached, as well as with respect tothemselves, if tWO or more substituents are present.

The substituents containing Si, B or P can be attached directly to thesilicon as is provided under the definition of R and R In suchinstances, one or more of the radicals R R or R in the formulas abovecan be replaced by a same group. The silyl groups are generallypreferred. The substituents which contain Si-Si or SiO-Si sequences areespecially valuable. They can be expressed by the formulas R SiSi(Rwherein R is defined as before and c is an integer up to 10. Thesegroups can be attached to the silicon of the four-membered ring throughoxygen or nitrogen as has been explained above for the simple silylgroups. Illustrative examples of some simple representatives arepentamethyldisilanyl, l-trimethylsilyl-tetramethyldisilanyl, 1- bis(trimethylsilyl) trimethyldisilanyl, pentamethoxydisilanyl,l-trimethoxysilyl-tetramethoxysilyldisilanyl, 1- bis(trimethoxysilyl)-trimethoxydisilanyl, pentamethyldisilanoxy,pentamethyldisiloxanoxy, pentamethyldisilanylamino,pentamethyldisilazanylamino, pentamethyldisilazanyl,pentamethyldisilazanoxy, etc.

When the substituents containing Si, B or P are attached to the siliconof the four-membered ring via a hydrocarbon radical, this radical ispreferably the divalent R of which the most important species aremethylene, ethylene, phenylmethylene, diphenylmethylene, phenylene,durylene, biphenylylene, methylene ether, ethylene ether,dimethyleneoxymethylene, 1,2-dimethyleneoxyethylene, diphenylene ether,1,4-dimethyleneoxyphenylene, 1,3-dimethyleneoxyphenylene,l,4-diphenyleneoxy phenylene, 1,3 diphenyleneoxyphenylene.

The starting diaminosilanes which can be subected to the transaminationare numerous. Some simple representatives arebis(methylamino)-dimethylsilane, bis(methyl amino) diphenylsilane,bis(methylamino)-pentamethylenesilane,bis(methylamino)-heptamethylenesilane, bis '(ethylamino)-difluorosilane.Regarding the amine radical which is released in the reaction, a lowboiling, cheap amine which can be recovered and used again will beselected. This selection, however, is also directed by the boiling pointof the intermediate diaminosilanes, since the reaction time can beconsiderably shortened at higher starting temperatures. As a rule,somewhat higher molecular radicals on the nitrogen atoms will bepreferred when those on the silicon atoms are lower molecular.

The transamination of diaminosilanes with mono-functional amines hasbeen reported from the literature. Bis (benzylamino) dimethylsilane,bis(anilin0) diphenylsilane and bis(vinyl0xy 2ethylamino)-dimethylsilane representing some symmetric diaminosilanesare known to have been prepared by transamination. The transamination iscarried out in similar manner with difunctional amines, i.e. diamines orcompounds containing two NH; groups, using a molar proportion of 2:1 ofthe reactants: 2R HNSi(R R )NHR +H NR In the transamination well knownfacts such as the strength of the SiN bond, which is affected by thesubstituents on the silicon and nitrogen, as well as steric 0ccurrenceshave to be respected.

Almost any available aliphatic, cycloaliphatic, araliphatic, aromaticand heterocyclic diamine is suitable for the preparation of the startingproducts or intermediary products respectively. Some qualifiedrepresentatives are hydrazine, guanidine, urea, ethylene diamine,1,3-diaminopropane, 1,2-diaminopropane, 1,4-diaminobutane,1,2-diaminobutane, 2,3-diaminobutane, 1,3-diaminobutane, 1,5-diaminopentane, hexamethylenediamine, 1,2-diaminocyclobutane, 1,2-,1,3-, l,4diaminocyclohexane, 4,4'-diaminobicyclohexane, 1,6diaminocyclododecane, o aminobenzylamine, 4,4'-diaminodiphenylmethane,'2,2-diaminobibenzyl, diaminobenzenes, beta,beta-diaminodiethylbenzenes,2,2-, 3,3'-, 3,4', 4,4'-diarninodiphenyl, 2,2'-diaminotolane, 2,2'-,2,4-, 4,4-diaminostilbene, 1.2-, 1,4-, 1,5-, 1,6-,1,8-diaminonaphthalene, diaminotetr-alines, diaminodecalins, 3,3-diaminobimesityl, 9,10-diaminoanthracene, 10,10'-diaminobianthryl,9,9-diaminobinaphthyl, 2,6-dia-minopyrazine, 2,4-, 4,5-, 2,6-,4,6-diaminopyrimidine, 3,7- diaminophenothiazine, 2,4-,2,5-diaminothiazoles, 2,6-diaminopyridine, 1,4 diaminopiperazine, 2,4diaminotriazine-1,3,5,5,6-diaminoindazole, diaminocarbazoles, 2,4-,4,7-, 4,8-diaminoquinazoline.

Besides these simple primary diamines are also considered aminocompounds having on their hydrocarbyl one or several substituents suchas halogen (e.g. diaminochlorobenzenes, -bromobenzenes, -fiuorobenzenes,2,4-dia'mino-6-chloropyrimidine, 1 diamino-Z-trifluoroethane), nitrogroups (e.g. diamino-nitrobenzenes, 4,4'-diamino-2"-nitrotriphenylmethane), cyano groups (e.g. diaminobenzonitriles),carbonyl groups (e.g. 1,3-diaminoacetone, 2,2'-,4,4-diaminobenzephenone, 4,4-diaminbenzils, 2,5'-, 2,6- diamino pbenzoquinone, o benzoquinone), hydroxyl groups (cg. 2,4diaminophenol,6,4-diamino-3hydroxydi phenyl, 3,4-diamino-1-naphthol,4,4-diaminobenzoin), mercapto groups (e.g.2,4-diamino-1,3,5-triazine-6-thiol), ether groups (e.g. aminoanisidines,4,4'-diarnino-3,3-dimethoxyl'biphenyl, 3,8-diaminodiphenylene oxide,4,5-diamino-2,6-dimethoxypyrimidine), 3,3 diaminoperfluorobicyclohexyloxide, thioether groups (e.g. 2,2'-, 4,4'-diaminodiphenylsulfide, 2,2'-,4,4-diaminodiphenyldisulfide, 2,2 diaminodiethylsulfide,4,5-diamino-2,6-dimethylmercaptopyrimidine), sulfonyl groups (eg,4,4-diaminodiphenylsulfone), 2,2-diaminodiethylsulfone, carboxylicgroups (e.g. diaminobenzoic acid, 4,4-diaminodiphenic acid,4,4'-diaminodiphenyl-3-carboxylic acid, beta,beta'- diaminoadipic acid,alpha,beta-, alpha-gamma-diaminobutyric acid), sulfo groups (e.g.4,4'-diaminostilbene-2,2- disulfonic acid), including the ester andamides of the acids, azo groups (e.g. 2,2'-, 2,4-, 3,3'-,4,4'-dia'minoazobenzene, 4,4'-diaminoazodiphenyl,4,4'-diaminobisazobenzene).

The reactants having acid groups are brought to reaction in the form ofan alkali salt. The free acid may be restored in the endproducts bytreatment with dilute acids.

The selection of the diamines which become the ring linking portion ofthe polymeric cyclodisilazanes conforms with the desired properties suchas stability, thermoplasticity, curability, solubility, etc. of thepolymers.

The intermediary compound (B) can be isolated. However, it is expedientto renounce the isolation and to carry out the subsequent pyrolyticdecomposition into the polymeric cyclodisilazanes in the same batch.

Whereas the transamination can be achieved at relatively lowtemperature, the formation of the polymeric cyclodisilazanes needshigher temperatures. The convenient temperature is difierent from caseto case and lies, as a rule, at least at the boiling point, if any, ofthe simple starting diaminosilane used in the reaction, or somewhatabove this temperature. In the course of reaction at firsttransamination to the higher boiling N,N'-bis- (aminosilyl)- diamineoccurs, allowing a gradual increase of the reaction temperature. Theease with which the transamination and the final cyclization andpolymerization proceeds, depends on the amine radicals, as well as onthe organic radicals present on the silicon. The more volatile and/orbasic the released amine is, and/ or the more electron-furnishing theorganic radical on the silicon are, the faster this reaction, as a rule,proceeds.

The amine which is split off in the transamination and also in the finalstep, and which is generally lower boiling than the diamine employed,has to be .removed continuously from the reaction mixture, since it. issupposed that the novel reaction is an equilibrium reaction. The removalof the amine may be accomplished in simple manner by continuousdistillation, possibly under reduced pressure. Other known methods ofelimination or inactivation of the released amine, of course, will notbe excluded.

The upper temperature limit of the reaction of invention is defined bythe decomposition point of the polymeric cyclodisilazanes to beprepared. This decomposition point is relatively high in most the casesand lies throughout above 400 C.

The course of reaction can be followed up quantitatively bydetermination of the amine quantity which is evolved. In all casesinvestigated till now the conversion lies between about and Thus, thenovel polymeric cyclodisilazanes are obtained by a simple heating of thereactants at an elevated temperature until no more substantial quantityof the primary amine is released.

It has been found that the polymeric cyclodisilazanes can also beobtained from compounds according to the Formula (B) wherein Y and Zsignify hydrogen atoms. In this process of invention there can be usedas starting compounds N,N'-disilyldiamines of the formula (F) R R Si-NRuNSiR R H I I H H which are easily converted upon treatment withelemental alkali metal into the corresponding polymeric cyclodisilazanesat relatively low temperatures, i.e. room temperature till about C. Whenthe starting com-pound (F) possesses a sufiicient acidity, depending onthe circumstances, also an alkaline earth metal or aluminum can be usedfor this purpose.

It is assumed that at first the corresponding salt, e.g. potassium salt--NK is intermediately formed with the imino groups NH- present,whereafzter the reaction proceeds instantaneously further according tothe scheme:

or (A) ZDKH 211B:

' action of, for example, chlorosilanes R R HSiCl with diamines (E). Onfurther investigating the reaction of invention it has been found thatinstead of an N,N'-bis(silyl)diamine (F) a mixture of a silane of theformula The simplest representatives are SiH SiFI-I SiF H and theorganically substituted derivatives. On principle, any silane having atleast two hydrogen atoms bound to the silicon atom can be used.

On practicing the process, a silane (G) and a diamine in a molar ratioof about 2:1 are brought to reaction in an inert solvent in the presenceof a catalytic amount of a metal, or metal hydride respectively, untilno more hydrogen evolution can be observed, or no more siliconhydrogenbonds can be detected in the infrared spectrum. Alkali metals and,depending on the circumstances, also aluminum can be used when they aredissolved by the reaction mixture, i.e., so far as the hydrogen being onthe nitrogen of the silylated amino group possesses a suflicient acidiccharacter. At the beginning of the reaction, the corresponding hydridewill be formed in any case. It was found that the quality (temperatureresistance) sometimes is improved when an excess amount of the silane(G) is used, thereby the appearance of amino groups (primary andsecondary amino groups) as terminal groups in the polymers will beavoided.

The reaction is expediently started by adding a hydride. Suitablehydrides are e.g. NaH, KH, LiH, BaH CaH AlH moreover complex hydridessuch as e.g. NaBH KBH4, NaAlH4, KAlH4, and In general, 0.1 tomole-percent of catalyst based on the diamine (E) or the intermediateN,N'-bis(silyl)diamine (F) respectively, are sufficient for the reactionif the catalyst will not be consumed in a hydrogenolytic side reaction.Hydroxyl and mercapto groups are expediently reacted previously withalkali metal. The conversion into the corresponding salts can be alsoachieved by a stoichiometric amount of hydride.

Not all catalysts possess the same activity. It was found that thereaction velocity decreases, for example, in the range of the metals KNa Li. The same is true of their hydrides. The reaction speed alsodepends on the solvent. Whereas, the activity of e.g. potassium orpotassium hydride in di-n-butyl-ether or hexane is not greatlydifferent, the lithium or lithium hydride in these solvents shows evenat 140 C. practically no activity. However, lithium or lithium hydrideare suitable catalysts in tetrahydrofuran or dioxane. The reaction canbe further promoted by the supplementary presence of strong tertiaryamines like trimethylamine, triethylamine, N,N'-diethylpiperazine, etc.,or cobalt chloride or colloid metals like cobalt, nickel and copper. Inprinciple, the intermediary step of the reaction of invention is a kindof dehydrogenation. But other well known dehydrogenation catalysts showno advantages over those proposed herein.

It is well known that the hydrides mentioned herein are less or morestrong reducing agents and can also provoke hydrogenolytic cleavages.Some of the previously enumerated substituents which can arise in thestarting compounds would normally be reduced. By appropriately selectingthe hydride and solvent, substituents otherwise reducible will bepreserved in the end-products. It is well known that, for example,compounds having the grouping SiOC, SiOSi, SiX, BOC, B*OB, BX, POC, POPor PX (X=Cl, F) are converted into the corresponding reduction products(silanes, borines or phosphines respectively, plus salts of the hydroxylconstituent cleaved) by, e.g. lithium-aluminum hydride only in a donorsolvent like ether, but not in e.g. hexane. Since the process ofinvention can be conducted also in solvents having no donor propertiesand thereto can be used hydrides like LiH, NaH and KH displaying muchless reducing power under the conditions employed, reduciblesubstituents such as enumerated above are possible. Thus, the kind ofhydride plays an important role. While, e.g. aromatic ketones, aliphatichalides, aromatic halides, acid anhydrides, esters, amides, imides,acetals, aliphatic nitriles, aromatic nitriles, aromatic nitro compoundsand certain double bonds will be reduced by lithium-aluminum hydride onheating in ether, no reduction will occur under the relatively mildconditions employed according to the invention with potassium hydride,being more appropriate than lithiumaluminum hydride. The qualificationof a defined hydride is ascertained in a preliminary experiment.

The reaction speed further depends on the temperature. In general,temperatures of between about and 150 C.

are sufficient. If necessary, however, also higher reaction temperaturescan be employed. The upper temperature limit is defined by thedecomposition point of the cyclodisilazane. This decomposition point ishigh and lies above 400 C. in most cases.

As a rule, a stoichiometric amount of hydrogen escapes during thereaction. But one can also use the evolving hydrogen for thehydrogenation of an unsaturated position, or reducible positionrespectively. These positions, able to take up hydrogen, can be presentin the reactants as well as in the solvents.

As a rule, the reaction is carried out in an inert solvent. Suitablesolvents are, e.g. straight-chain and branched-chain parafiins having upto about 10 carbon atoms in the molecule like propane, n-butane,n-pentane, iso-pentane, n-hexane, iso-hexane, 2,4,4trimethylpentane,n-octane, iso-octane, n-decane, etc.; cycloparaffins like cyclohexane,methylcyclohexane, cyclopentene, cyclohexene, cyclohexadiene, etc.;aromatic hydrocarbons like benzene, toluene, xylene, ethylbenzene,monoand dialkylnaphthalenes, e.g. l-methylnaphthalene, 1,4-dimethy1-naphthalene, l-ethylnaphthalene, 2-ethylnaphthalene; hydroaromatichydrocarbons like tetralin, decalin, etc.; moreover chlorinated andfluorinated derivatives of the above-mentioned hydrocarbons; moreoveraliphatic ether like methylethylether, ethylether, iso-propylether,n-propylether, allylether, ethyl-n-butylether, n-butylether,isobutylether, benzymethylether, ethyleneglycoldimethylether,ethyleneglycoldiethylether, diethyleneglycoldimethylether, etc.;aromatic ether like anisol, phenetol, veratrol, phenylether,phenyl-allylether, phenyl-benzylether, etc.; cyclic ether like furan,tetrahydrofuran, tetrahydrofurfurylethylether, dioxane, etc. Moreover,some qualified solvents are acetonitrile, benzonitrile, acetone,diethylketone, dimethylsulfone, dimethylsulfoxide,tetramethylenesulfoxide, dimethylformamide, dimethylacetamide,ethylacetate, N-ethylmorpholine, pyridine, N,N-dialkylpiperazines,tetramethylurea, etc. The choice of the appropriate solvent is directedby the solubility of the catalyst and the reducing power. When thereactants and the endproduct are soluble at the reaction temperature,the process can be conducted also without a solvent.

It depends on the organic group R which of the compounds (A) or (A')will be formed in the pyrrolytic process (a) as well as in the catalyticprocess ([2). When R is such an organic group which does not allow aring closure via the two nitrogen atoms which it contains, the compound(A) will be formed. Such organic groups are e.g. alkylene groups havingthe two nitrogen atoms more distant than 3 carbon atoms like in, e.g.the intermediary starting compounds 1,4-diaminabutane and1,6-diaminohexane, or arylene groups having the two nitrogen atoms inmeta or para-position like in, e.g. 1,3-diaminobenzene and1,4-diaminobenzene. On the other hand, using, e.g. 1,2-diaminoethane,1,3-diaminopropane, 1-2-diaminobenzene, or the N,N-disubstitutedderivatives, respectively, the resulting endproducts will have thestructure (A') shown at the beginning of this specification. Suchpolymers are embodied in the Examples 7, 12, and 17.

The polymers are more resistant if they are freed of the catalyst. Thehydrides can be eliminated by washing with methanol. When the polymersare soluble, they can be extracted with a suitable solvent in order toachieve the purification. Depending on the circumstances, thepurification can be also achieved by washing with water or dissolving inwater and reprecipitation.

The molecular weight of the polymers can be varied in usual manner byaddition of chain-terminating agents. Monohydrosilanes of the formula RSiH, wherein R has the previous significance, are especially suited.

The polymers are liquid, waxy, glassy, glutinous or rubber-like and maybe fiber-forming according to the organic radicals R R and R If theycontain carboxylic, sulfo or other acid groups they can be soluble inwater in the form of their alkali salts and become insoluble onacidifying. They can also be more or less cross-linked and insoluble inany solvent. They are resistant at temperature up to 500 C. and more andmay even be useful at temperatures up to 1000 C. Many of the polymerscan be processed by the usual thermoplastic methods, such as extrusion,injection molding, blown, calendered and extruded film and some other byconventional rubber molding techniques such as compression and transfermold. The hard types of polymeric cyclodisilazanes are casting resinswhich are workable by using cutting machines, or the polymerization hasto be carried out during the fabrication. The foamed polymers can beprepared in known manner by addition of blowing agents likeazo-bis-isobutyronitrile, dinitrosohexamethylenetetraamine, etc. Theamine or hydrogen which is split off in the reaction can also act as ablowing agent. Especially suited are methylamine and ethylarnine.

A further object of this invention is the use of the polymericcyclodisilazanes in the preparation of coatings, films, impregnations,etc. For this purpose the mixture of the starting reactants, i.e. thediaminosilane plus diamine, or the intermediateN,N'-bis(aminosilyl)diamine, or the silane plus diamine plus catalyst,or the N,N-disilyldiamine plus catalyst is applied to a substratum andsubjected to such temperatures, as the formation of higher polymerized,possibly cross-linked synthetic composition coatings is achieved Or thepolymer is applied in a solvent such as hexane, benzene,tetrahydrofuran, acetone, ether, methanol, ethanol, etc. Afterevaporation of the solvent, the polymer possibly can be baked on theirsupport. The polymers are excellently suited for lacquers andimpregnations of substrates such as paper, textiles, leather, plastics,wood, glass, metals, rubber, etc. The polymers can contain as additivesother constituents such as powdered wood, asbestos, glass fibers, metalfibers, pigments, etc., thereby their mechanical properties will bemodified.

EXAMPLE 1 A mixture of 9.21 g. (0.05 mol) benzidine and 27.04 g. (0.1mol) bis(ethylamino)diphenylsilane is heated in a flask provided with athermometer reachng into the melt, and with a reflux condenser. At atemperature of about 190 a significant evolution of ethylarnine begins.In the course of 21 hours the temperature is raised to 400 C. Theescaping ethylarnine is collected in 1 N HCl and estimated by titration.From this the conversion is calculated, as it also is in the followingexamples. The flask content thickens gradually but is still liquid at60% conversion (270 C.). From 70% conversion the mixture is solid and at400 C. (final temperature) can no longer be melted. Based on the amountof ethylarnine split off, the conversion amounts to 96.7% of thetheoretical value.

An impurity is removed by extracting the obtained mass with hexane for15 hours. Yield 26.2 g. (96.4%).

The polymer obtained is a hard, not too brittle mass of light yellowcolor. It is insoluble in the usual organic solvents and in water, evenafter prolonged boiling.

Analysis.C H N Si (544.8 per unit). Calcd (percent): C, 79.37; H, 5.18;N, 5.14. Found (percent): C, 77.21; H, 5.02; N, 5.88.

The same starting mixture is heated at 180 to 370 C. within 45 hoursusing, however, 160 g. of terphenyl as solvent. The resulting mass isextracted with cyclohexane for 53 hours to remove some impurities.

EXAMPLE 2 g. (0.05 mol) bis(ethylamino)dimethylsilane is heated as inExample 1. At a temperature of about 134 C. a significant evolution ofethylarnine begins. The temperature of the mixture is increased to 390C. in the course of 15 hours. The flask content is still fluid at 75%conversion (280 C.) and then thickens quickly and at 390 C. (finaltemperature) it can no longer be melted. Based on the amount ofethylarnine split 01f, the conversion is 95.2% of the theoretical value.An impurity is removed by extracting the obtained mass with hexane for15 hours.

A mixture of 4.60 g. (0.025 mol) benzidine and 7.32 Yield 7.01 g.(94.6%). The polymer obtained is a transparent, bright yellow, viscousmass and has no M.P.

Analysis.C ,-H N Si (296.5 per unit). Calcd (percent): C, 64.81; H, 6.80N, 9.45. Found (percent): C, 64.46; H, 6.90; N, 10.54.

EXAMPLE 3 A mixture of 12.0 g. (0.06 mol) 3,3-diaminodiphenyl ether and24.25 g. (0.12 mol) -bis(n-butylamino)dimethylsilane is heated as inExample 1. At a temperature of about 110 C. a significant evolution ofn-butylamine begins. Because the reaction partners are not very soluble,the mixture is stirred to a conversion of 45% (180 C.). The temperatureof the mixture is increased in the course of 9 hours to 400 C. The flaskcontent is liquid at a conversion of 84% (320 C.) and highly viscous inthe cold. The clear, bright yellow melt begins to foam at 370400 C. andthen hardens to a gummy mass. According to the amount of butylaminesplit off, the conversion amounts to 91% of the theoretical value.

The polymer obtained is a brown, thermoplastic mass. It can be freed ofa small amount of glutinous substance by extraction, e.g. with methylchloride. The polymer swells under the influence of many organicsolvents. An impurity is removed by extracting the obtained mass withhexane for 15 hours. Yield 16.7 g. (90.8%).

Analysis.-C H ON Si (312.5 per unit). Calcd (percent): C, 61.49; H,6.45; N, 8.96. Found (percent): C, 61.10; H, 6.31; N, 9.19.

EXAMPLE 4 A mixture of 29.2 g. (0.1 mol) bis(l,3-aminophenoxy)-phenylene-(1,3) and 29.2 g. (0.2 mol) bis(ethylamino)-dimethylsilane isheated as in Example 1. At a temperature of about 128 C. a significantevolution of ethylarnine begins. The temperature is increased to 400 C.during the course of 7 hours. The mixture is stirred as long as it ispossible. It is still liquid at a conversion of about 50% (300 0.),becomes more and more viscous at a conversion range up to and thenfinally at 400 C. (final temperature) solidifies to a gummy mass. Basedon the amount of ethylarnine split off, the conversion is 96.8% of thetheoretical value. An impurity is removed by extracting the obtainedmass with methylchloride for 40 hours. Yield 95.3%.

The polymer obtained is a brown, thermoplastic mass. It swells under theinfluence of many organic solvents.

Analysis.- C H O N Si (404.6 per unit). Calcd (percent): C, 65.30; H,5.98; N, 6.92. Found (percent): C, 65.05; H, 5.73; N, 7.38.

The same product is obtained when bis(n-butylarnino) dimethylsilane isused instead of bis(ethylamino)dimethylsilane.

EXAMPLE 5 1.84 g. (0.01 mol) of benzidine and 3.68 g. (0.02 mol) ofdiphenylsilane are dissolved in 30 ml. of pure dimethoxyethane and 0.104g. (0.0043 mol) of sodium hydride is added at 22 C., whereupon avigorous evolution of hydrogen occurs. After about 3 hours 80-90% of thetheoretical amount of hydrogen is split off. The mixture is kept forsome time at the boiling point of the solvent (86 C.) until no moresubstantial amount of hydrogen escapes.

The yellowish polymer is filtered off, washed first with hexane and thenwith methylalcohol and dried at 80 C. Yield 4.96 g. (91.0%).

Analysis.-C H N Si (544.8 per unit). Calcd (percent): C, 79.37; H, 5.18;N, 5.14; Si, 10.31. Found (percent): C, 77.21; H, 5.02; -N, 5.88; Si,9.58.

The polymer is insoluble in the common organic solvents. The samemixture is heated at 50 to C. in 5 hours, using 60 ml. of xylene insteadof 1,2-dimethoxyethane. The xylene is distilled off and the residue istreated with cold methyl alcohol for 3 hours and then extracted withhexane to remove further impurities. Yield 5.4 g. (98.5%).

EXAMPLE 6 A mixture of 1.08 g. (0.01 mol) p-phenylenediamine 3.68 g.(0.02 mol) diphenylsilane and 0.063 g. (0.0026 mol) sodium hydride in 30ml. dimethoxyethane is heated from 22 to 81 C. in 4 hours. The hydrogenrecovered corresponds to 98% conversion. The product is precipitatedwith hexane, washed with methanol and dried in vacuo at 80 C. Yield 4.51g. (96.2%). The polymer is a slightly yellowish powder, insoluble in thecommon organic solvents.

Analysis.C H- N Si (468.7 per unit). Calcd (percent): C, 76.88; H, 5.16;N, 5.98. Found (percent): C, 76.90; H, 5.13; N, 5.69.

EXAMPLE 7 1.202 g. (0.02 mol) of ethylenediamine, 7.373 g. (0.04 mol) ofdiphenylsilane and 10 mg. of sodium hydride are reacted in 20 m1. ofdimethoxyethane. A vigorous evolution of hydrogen occurs at 30 C. Thereaction temperature is increased to 85 C. in 3 to 4 hours. The solventis distilled off at 50 C./ 0.01 mm. The remaining viscous and somewhatglutinous polymer is stirred with hexane and filtered 01f. Yield 8.08 g.(96.0%). The polymer is treated with methylalcohol at room temperaturefor one hour and dried at 50 C./0.01 mm. The polymer gives a clear meltat about 120 C. It is soluble in benzene and ether.

Analysis.--C H ,N Si (420.67 per unit). Calcd (percent): C, 74.23; H,5.75; N, 6.66; Si, 13.35. Found (percent): C, 73.62; H, 5.89; N, 7.02;Si, 12.00.

The polymer displays the same properties when it is prepared in benzeneinstead of dimethoxyethane. The polymer contains1,3-diaza-Z-sila-cyclopentane ring units whose nitrogen atoms are linkedvia silyl groups to form the polymer.

EXAMPLE 8 1.76 g. (0.02 mol) of 1,4-diaminobutane, 7.37 g. (0.04 mol) ofdiphenylsilane and 5-10 mg. of sodium hydride are reacted in 20 m1. ofdimethoxyethane at 86 C. for 5 to 6 hours. The mixture is worked up asin the foregoing example. Yield 8.21 g. (91.5%). The polymer softens atabout 61 C. and gives a clear melt at about 90 C. It is a mobile liquidat 200 C. It is soluble in benzene and ether.

Analysis.--C H N Si (448.73 per unit). Calcd (percent): C, 74.95; H,6.29; N, 6.24; Si, 12.52. Found (percent): C, 72.75; H, 6.26; N, 5.85;Si, 10.42.

There is also obtained 0.78 g. of a liquid polymer which is soluble inhexane.

EXAMPLE 9 2.32 g. (0.02 mol) of 1,6-diaminohexane, 7.37 g. (0.04 mol) ofdiphenylsilane and 510 mg. of sodium hydride are reacted in 20 ml. ofdimethoxyethane at 84-86 C. for 5 to 6 hours. The solvent is distilledoff. The hard residue is pulverized, treated with methylalcohol, andextracted with hexane for one hour. Yield 0.58 g. soluble in hexane. 9.0g. (94.4%) insoluble in hexane. The polymer gives a clear melt at about150 C.

Analysis.C H N Si (476.78 per unit). Calcd (percent): C, 75.57; H, 6.77;N, 5.88. Found (percent): C, 74.83; H, 6.70; N, 5.93.

EXAMPLE 10 3.96 g. (0.02 mol) of 4,4'-diaminodiphenylmethane, 7.37 g.(0.04 mol) of diphenylsilane and 5 to 20 mg. of sodium hydride arereacted in 20 m1. of xylene at 100- 140 C. for 4 to 6 hours. The mixtureis stirred with hexane and the polymer precipitates together with thesodium hydride and filtered 01f. The polymer is then treated withethylalcohol at 25 C. for 2 hours, filtered off and dried at 100 C./0.0lmm. Yield 9.98 g. (89.3%).

16 Analysis.-C H N Si (558.84 per unit). Calcd (percent): C, 79.52; H,5.41; N, 5.01. Found (percent): C, 79.31; H, 5.49; N, 4.66.

EXAMPLE 11 EXAMPLE 12 2.16 g. (0.02 mol) of 1,2-diaminobenzene, 4.32 g.(0.04 mol) of phenylsilane and 5 to 20 mg. of sodium hydride in 50 ml.mesitylene are reacted in 50 ml. mesitylene at 158 C. for 15 hours. Thesodium hydride is removed. After having distilled off the solvent, theresidue is extracted with hexane for 15 hours to remove impurities.Yield 6.1 g. (95.9%).

Analysis.C H N Si (316.5 per unit). Calcd (percent): C, 68.30; H, 5.10;N, 8.85. Found (percent): C, 67.91; H, 5.15; N, 9.47.

EXAMPLE 13 3.68 g. (0.02 mol) of benzidine, 4.32 g. (0.04 mol) ofphenylsilane and 5 to 20 mg. of sodium hydride are reacted in 40 ml.mesitylene for 8 hours and Worked up as in Example 12. Yield 7.5 g.(95.1%

Analysis.C H N- Si (392.6 per unit). Calcd (percent): C, 73.42; H, 5.13;N, 7.14. Found (percent): C, 71.29; H, 4.86; N, 7.49.

EXAMPLE 14 3.96 g. (0.02 mol) of 4,4'-diaminodiphenylrnethane, 4.32 g.(0.04 mol) of phenylsilane and 5 to 20 mg. of sodium hydride are broughtto reaction in 40 ml. of l-phenyldodecane at 240 C. for 5 hours. Thesodium hydride is filtered 01f, the solvent evaporated and the residueextracted with hexane for 15 hours to remove impurities. Yield 8.0 g.(98.8%).

Ana[ysis.C H N Si (406.6 per unit). Calcd (percent): C, 73.84; H, 5.45;N, 6.89. Found (percent): C, 71.49; H, 5.25; N, 7.12.

EXAMPLE 15 3.68 g. (0.02 mol) of 4,4'-diaminodiphenyl, 4.88 g. (0.04mol) of methyl-phenylsilane and 5 to 20 mg. of sodium hydride arereacted in 20 ml. of 1,2-dimethoxyethane at C. for 3 hours. The reactionproduct is worked up as in Example 14. Yield 8.1 g. (96.3%).

Analysis.C H N Si (420.7 per unit). Calcd (percent): C, 74.23; H, 5.75;N, 6.66. Found (percent): C, 73.94; H, 5.71; N, 6.77.

EXAMPLE 16 3.96 g. (0.02 mol) of 4,4-diaminodiphenylmethane, 4.88 g.(0.04 mol) of methyl-phenylsilane and 5 to 20 mg. of sodium hydride arereacted in 40 ml. of xylene at C. for 11 hours. The sodium hydride isfiltered off, the polymer precipitaated by hexane, separated andextracted with hexane for several hours. Yield 8.5 g. (98.2%).

Analysis.C H N Si (434.7 per unit). Calcd (percent): C, 74.60; H, 6.03;N, 6.44. Found (percent): C, 74.26; H, 5.91; N, 6.48.

EXAMPLE 17 0.74 g. (0.01 mol) of 1,3-diaminopropane, 3.68 g. (0.02 mol)of diphenylsilane and 0.06 g. (0.0025 mol) of 1 7 sodium hydride areheated in 40 ml. of 1,2-dimethoxyethane at 30 to 80 C. in hours. Themixture is worked up as in Example 7. Yield 4.0g. (92.8%

The polymer contains 1,3-diaza-2-silacyclohexane ring units, whosenitrogen atoms are linked via silyl groups to form the polymer.

Analysis.-C H N Si (434.7 per unit). Calcd (percent): C, 74.70; H, 6.03; N, 6.44; Si, 12.92. Found (percent): C, 74.34; H, 6.41; N, 6.76; Si,12.18.

Softening points of the polymers The softening points are defined by thetemperature at which a metal rod, pressed at 2.3 kg./cm. enters acompact piece of polymer (5 mm. high) of its depth. A constant rate ofheating of 2 C. per minute was applied.

Polymer of example: Sotfening point,

The product of Example 1 is similar to that of Example 5. The polymersof Examples 3 and 4 are glutinous.

4. A polymeric cyclodisilazane of claim 1 formula 5. A polymericcyclodisilazane of claim 1 formula 6. A polymeric cyclodisilazane ofclaim 1 formula formula 3O formula THERMOGRAVIMETRIC ANALYSES-WEIGHTRESIDUE PERCENT [Heating rate, 2.8 C./min.; atmosphere, nitrogen] of theof the of the 7. A polymeric cyclodisilazane of claim 1 of the 8. Apolymeric cyclodisilazane of claim 1 of the Polymer of 200 250 300 350400 450 500 550 500 550 700 750 800 850 900 example 9s. 5 93. 5 97. 582.5 73 43 95 31. 5 29.5 29 29 2s. 5 25 100 100 98 95 85 79 73. 5 59. 557 55.5 55.5 55.5 55. 5 55.5 100 95. 5 95. 5 90 92. 5 72. 5 50 5o. 5 45.5 45 45 45 44.5 100 100 100 97. 5 92. 5 s4. 5 75. 5 72.5 70 59 59 59 5959 100 100 98. 5 95. 5 s9 s2 75 70 55. 5 57. 5 57 57 57 57 100 100 97. 592. 5 s2. 5 72. 5 55.5 52. 5 51 51 51 51 51 51 What is claimed 1s: 9. Apolymeric cyclodrsilazane of claim 1 of the 1. A polymeric cyclosilazaneof the formula RlR2si N R3 NSiR R7 5 wherein R and R taken singly areeach hydrogen atoms, fluorine atoms or hydrocarbyl groups which can havehalogen atoms, alkoxy groups, aroxy groups and silyl groups assubstituents, R and R taken together with the silicon atom to which theyare attached form a heterocyclic group, R is a hydrocarbylene group or ahydrocarbylene ether group which can have halogen atoms, alkoxy groups,aroxy groups and silyl groups as substituents, a is O or 1, and prepresents the number of repeating units, provided R is such a groupthat does not allow ring closure and R separates the nitrogen atoms bymore than 3 aliphatic carbon atoms or meta or para spaced nitrogen atomson an aromatic ring.

2. A polymeric cyclosilazane of claim 1 wherein R and R are eachhydrocarbyl having not more than 8 carbon atoms, R is hydrocarbylenehaving not more than 24 carbon atoms, and a is 1.

3. A polymeric cyclosilazane of claim 1 wherein R and R are eachhydrocarbyl having not more than 8 carbon atoms, R is a hydrocarbyleneether having not more than 24 carbon atoms and a is 1.

formula formula formula formula 13. A polymeric cyclodisilazane of claim1 of the [(phenyDHSi-N --NSiH (yhenyl) (p v h (p e v h 10. A polymericcyclodisilazane of claim 1 of the 11. A polymeric cyclodisilazane ofclaim 1 of the 'Q QH 12. A polymeric cyclodisilazane of claim 1 of the14. A polymeric cyclodisilazane of claim 1 of the [(phenyDHSi-N formulaQfl l 15. A polymeric cyclodisilazane of claim 1 of the formula NSiO H3(phenyl) 16. A polymeric cyclodisilazane of claim 1 of the formula-NSiCHa(Dhenyl) '17. A diaminodiorganosilane of the formula R R siN-R,Nsi1 rt z 11 11 2' wherein R R R and a are as defined in claim 1 and Zis a cleavable amine group, volatile at reaction temperature, at atemperature gradually increasing toward the decomposition point of thepolymeric cyclosilaza-ne until no significant amount of amine is splitoff.

19. A process of claim -18 wherein said diaminodiorganosilane is made insitu by heating a diaminodiorganosilane of the formula SiR R Z wherein RR and Z are as defined in claim 18, with a diamine of the formula H NRNH wherein R and a are as defined in claim 18, in a molar proportion ofat least about 2:1, at a temperature gradually increasing toward thedecomposition point of the polymeric cyclosilazane until no significantamount of amine is split off.

'20. A process for the preparation of a pOlymeric cyclosilazane of claim2 comprising heating a diaminodiorganosilane of the formula SiR R Zwherein R and R are as defined in claim 2 and Z is a cleavable aminegroup volatile at reaction temperature, with a diamine of the formula HNR NH wherein R is as defined in claim 2, in a molar proportion of atleast about 2:1, at a temperature gradually increasing toward thedecomposition point of the polymeric cyclosilazane until no significantamount of amine is split olf.

21. A process for the preparation of a polymeric cyclo- 2Q silazane ofclaim 3 comprising heating a diaminodiorganosilane of the formula SiR RZ wherein R and R are as defined in claim 3 and Z is a cleavable aminegroup volatile at reaction temperature, with a diamine of the formula HNR NH wherein R is as defined in claim 3, in a molar proportion of atleast about 2:1, at a temperature gradually increasing toward thedecomposition point of the polymeric cyclosilazane until no significantamount of amine is split off.

22. A process for the preparation of the polymeric cyclosilazanesofclaim 1, comprising treating at a temperature at least sufiicient tosplit oif hydrogen a silazane of the formula wherein R R R and a are asdefined in claim 1, in an inert solvent with at least a catalytic amountof potassium, sodium or lithium, or hydride thereof.

23. A process of claim 22 wherein said silazane is made in situ bytreating a silane of the formula R R SiH wherein R and R are as definedin claim 22, with a diamine of the formula H NR ,,-NH wherein R is asdefined in claim 22, in a molar proportion of at least 2:1 silane todiamine, in an inert solvent with at least a catalytic amount ofpotassium, sodium or lithium, or hydride thereof, at a temperature inthe range of about 20 to C.

24. A process of claim 23 wherein said solvent is an ether.

References Cited UNITED STATES PATENTS 3,172,874 3/1965 Klebe 26023,207,707 9/1965 Klebe 260448.2 3,228,895 1/1966 Burks et a1. 26023,297,592 1/1967 Fink 2602 3,311,571 3/1967 Burks et a1 2602 3,354,09811/1967 Byrd 2602 FOREIGN PATENTS 1,425,306 12/1965 France.

OTHER REFERENCES Fink: Silicon-Nitrogen Heterocycles, Angew. Chem.Internat. Edit, vol. .5, 1966, No. 9, pp. 760 to 774.

DONALD E. CZAJA, Primary Examiner.

M. I. MARQUIS, Assistant Examiner.

US. Cl. X.R.

